The specific aims and long-term objectives of this proposal are to use heterocumulenes (ketenes, ketenimines, and their synthetic equivalents) for new applications in asymmetric catalysis, namely the asymmetric synthesis of p-lactams (especially the trans diastereomers), catalytic asymmetric halogenation (chlorination, bromination and iodination), and catalytic asymmetric a-nitration. We also propose the development of new bifunctionally (Lewis acid-chiral nucleophile) catalyzed asymmetric reactions, including [2+2] as well as [4+2]cycloadditions of ketene enolates. All the chiral, optically enriched products of our reactions are meant to be either pharmacologically active, or to represent key intermediates and branch points in the synthesis of medicinally or academically interesting target molecules. In order to benefit public health, we have established a collaboration with Dr. Samuel Deanmeade, M.D. (JHU Med.) to synthesize p- lactams to develop a new, sensitive test for prostate specific antigen (PSA). PSA is a marker for prostate cancer, and its measurement may be useful to facilitate diagnosis of the disease.